Riley was picked 25th overall in the first round of the 1974
NFL draft by the
Minnesota Vikings. He played 11 seasons, all with the Vikings, from 1974 to 1984. He appeared in 138 games, making 128 starts. He was a part of the 1974 and 1976 NFC championship teams. He played in
Super Bowls IX and
XI. Riley took over the starting left tackle position in 1976 and started every game until early 1978 when a neck injury put him on the injured reserve game for 11 games. Riley returned to full-time duty in 1979 and started every game for the next five seasons. Over his career, Riley helped the Vikings reach the playoffs seven times. He started in
Super Bowl XI to cap that season and helped Minnesota advance to the 1977 NFC Championship game. In his last year, Riley started every game despite playing the entire season with his left hand in a cast because of a broken thumb. He started the first six games at left tackle however, in attempt to decrease the amount of contact to his injured hand, he was moved to right tackle for games 7 through 11. Riley went back to left tackle for the remainder of the season as his teammate said the blind side position was too challenging. ==Awards and honors==